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Missing Storage Space on Raid SCSI Drives

Hello All,

I just became the owner of a Server with 5 SCSI drives. The problem I'm having is after setting up the server and configuring the array to Raid5 with all 5 Drivers, I'm suppose to get 16GBs of storage room while 4GBs is used for rebuilding/transfering. However, every time I try to configure it, it keeps showing just 4GBs and the rest is missing.

I am not sure what you are saying You have 5 drives, you expect 16Gb for storage and 4Gb for transfers..................that gives you 20Gb right, so they are 4Gb drives?

I think that you have RAID5 with mirroring?

2 drives have the operating system and apps on them and are mirrors of eachother. That should leave you with three drives for data, but only two would appear as the third one allows the redundancy and recovery.

That should still give you 8Gb though?

Can you confirm:

1. That the BIOS can see all the drives
2. They are all correctly connected in the array.
3. That you are mirroring your OS and apps.
4. The drives are 4 Gb each
5. The 4Gb that you can "see" is the storage part of the array.

It sounds as if you might have set up a RAID 1+1 array inadvertently? or one of the other strange combinations (they go from RAID0 to RAID16 to my knowledge )

Ok, yes, your assumsion that they drivers are 4GBs is correct (4.3 to be procise). The BIOS does see the drivers as well. All drivers light up and are recognized by the array. The 4GB part is where I can install my OS (windows 2000 server) and the rest disappears.

I've gone through the array setup (several times) to ensure I was putting it at Raid 5 (had choice between 0,1+0,1,4,and 5) and once done, save configuration to the controller and reboot to install the OS. Raid 5 is suppose to be 80%write and 20%guard for datatransfer in case a drive fails, giving me 16GB of accessible memory and 4GB for failure (yank a drive and replace with a new one for rebuild), but I get the reverse?

As I am sure you are aware, this is a very old bit of kit..................when I first started with RAID arrays a 9Gb drive was the smallest I encountered, and those were obsolete boxes.

I am wondering if, because of its age, your system might work somewhat differently from what we would expect today?

A classic or traditional RAID5 array will stripe blocks of data across ALL the drives, and maintains parity data on all of them ( a bit like a Borg Cube?) This will include your OS and applications. You can afford to lose 1 drive and still be able to rebuild the array. The 80/20% thing is theoretical, as you can run RAID5 on only three drives (one of which would have to be redundant). As you have 5 drives the 20% rule does work, however, as that is a whole drive.

I am wondering:

giving me 16GB of accessible memory and 4GB for failure (yank a drive and replace with a new one for rebuild), but I get the reverse?

It sounds as if your system may be reporting redundancy, rather than available/used space. Perhaps there is some controller setting to change this, or at least see the other side of the coin?

I am guessing that you don't have much in the way of documentation or help files, given that the kit is that old? so it will be difficult to test this without a practical experiment.

What I would be inclined to do is set the array up, load your operating system, and try squirting 8Gb of data into it. If it comes up with a disk space error, then we will know that the array is not setting up properly. If it doesn't then we know that it is the way the reporting is set up?

I am also curious as to what the Windows 2000 OS shows as disk space.

That is the best I can think of at the moment. What make model of controller is it, maybe I can find out some more?

i havent looked inside my server for afew months, i do belive its a scsi hardware card
sometimes the drives show up as defunct *no idea what that means really*
sometimes they show up as critical, all depends on what order i put all 5 in

this server has pcdoctor 2000 built in... and i have a raid config disk aswell... they see the drives but i cant configure them, and i cant get them to register at all in linux

this server WAS working when it was last online, then it sat on a shelf for 5 years... now its in my house *bastard weighs about 100lbs and sounds like a jet engin*

if i cant figure it out soon im probably going to bring it into a local computer shop, or call up IBM and have a nice long chat with them after a half hour of phone switching systems *sigh*

It might help if you gave me a full run-down on what you have. Make/model/size/software/version/SP or whatever.............then I can look stuff up without having to prolong things by asking you and waiting for a reply?

What is the original OS, and what OSes are on it now.............which does it boot to?

If you have 5 drives then you must have a SCSI controller card............best I have off a MoBo will offer RAID0 or RAID 1 as it only has two onboard connectors.

My question was how is your RAID controlled. With 5 drives it should be with a RAID controller card, which should be separate from the SCSI card, and the RAID card should have its own BIOS.

You say that you get "defunct" (that should mean "dead") or "critical" which should mean about to die. You also say that it does not matter what order you have put them in as?............that makes me suspect the cable/connections. Do you get errors from the same positions?

Sorry that I cannot be more positive as yet, but RAID is difficult to support from a distance

It is mot that it is "mystical" or "complex", it is just that there are so many more combinations and factors to take into account

hmmm... normaly the old boxes RAID5 combo's are no different from a new RAID5, I have an old RAID5 server running with hotplug 2.1 GB SCSI disks, this thing sounds like a jet too You can hear every disk spinning up to its speed when you switch it on.

The config is simple RAID5 with 5 disks resulting in 8GB usefull space. Every disks hold data so that the array can rebuild when there is a failure of one disk.
Are you sure you placed all the disks in the same array?

The best way to work is to clear the RAID config and clear the data on the disks (if you don't need them) and start a new clear raid array configuration from the cd or disk that manages that server (like compaq gave out with their proliant servers) It's very straightforward to config a raid with those tools. I bet IBM has a similar system, or probably you need to press a F key to enter the RAID config info.